In many electronic systems various components, such as transistors, rectifiers, transformers and inductors, generate a substantial amount of heat during operation. In order to ensure that the components are not damaged during such operation, it is necessary that the heat generated by such devices be dissipated. Heat dissipation is typically done by means of a cooling apparatus, such as a heatsink.
There are a number of factors that must be considered in connection with the design of a heatsink apparatus. First, in order to maximize the thermal transfer between the components and the heatsink, it is desirable to have the heat transfer surface of a given component positioned in direct thermal contact with the heatsink. In some heatsink assemblies, the components are mounted on a thermally conductive base, which is then thermally coupled to the heatsink One disadvantage of this design is that the base, although thermally conductive, still offers some amount of thermal impedance, particularly at the base interface, making the overall cooling system less efficient. A consequence of the thermal inefficiency is that such systems may have to rely upon a larger heatsink to effect cooling, which has the disadvantage of taking up more space.
Secondly, the ease of assembling the components together with the heatsink, and the integration of that assembled unit with the rest of the system are an important concern. Since such assembly and integration are typically performed in a large scale manufacturing environment, it is desirable to have a non-labor-intensive design, involving a minimal number of easily combined parts.
Thirdly, the components that are to be cooled through the heatsink may have relatively wide dimensional tolerances. Such dimensional tolerances between the same types of components may not prove to be problematic when each component is mounted on its own heatsink. In those systems in which multiple components are cooled by the same heatsink, however, such dimensional variations may affect the successful coupling of the multiple heat transfer surfaces with a common heatsink.
Finally, in addition to the dimensional tolerances which result from the original manufacturing of the component, it is also common for the dimensions of a given component to change over time due to the creep of the material--such as plastic--out of which the component is constructed. This is also true with respect to components that are exposed to the expansion and contraction which results from thermal cycling. Accordingly, it is desirable to design a heatsink apparatus which accommodates dimensional variations between different components which are to be mated with a common heatsink, as well as the possible changes in dimension of a given component during its useful life.